The release of drugs from an implanted medical device has been shown to be beneficial for the function of devices and the treatment of various medical conditions. For example, delivery of a drug from the device surface can prevent cellular responses initiated by the presence of the implantable device. Also, drug released from the device can prevent conditions that would otherwise shorten the functional life of the device following implantation. Drug released from the device may also be directed at treating a diseased area of the body.
Some implantable devices simply have a drug applied to the device surface. Such preparations are generally undesirable because the drug can be easily removed from the surface during insertion.
Implantable medical devices having thin polymeric coatings containing therapeutic compounds protect and control the release of drug from the device surface. Such devices have been shown to be particularly valuable for the treatment of diseases of the cardiovascular system. However, these polymeric coatings may not be ideal for applications involving the transient insertion of a medical device to a target tissue in the body.